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प्रश्न
Identify the figure and give its use.
Identify a figure and write one use of it:
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उत्तर
Figure: Cartridge type fuse/Electric fuse
Uses:
- It is a safety device that protects the wiring from overheating caused by an excessive current supply.
- It melts when a high current travels through the circuit, causing the circuit to break and the current to stop flowing through it.
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संबंधित प्रश्न
Why does the cord of an electric heater not glow while the heating element does?
An electric heater is connected to the 230 V mains supply. A current of 8 A flows through the heater.
(a) How much charge flows around the circuit each second?
An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?
Write down the formula for the heat produced when a current I is passed through a resistor R for time t.
A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.
What is meant by the heating effect of current? Give two applications of the heating effect of current.
The current passing through an electric kettle has been doubled. The heat produced will become:
(a) half
(b) double
(c) four time
(d) one-fourth
The elements of electrical heating devices are usually made of:
(a) tungsten
(b) bronze
(c) nichrome
(d) argon
An electric iron is connected to the mains power supply of 220 V. When the electric iron is adjusted at 'minimum heating' it consumes a power of 360 W but at 'maximum heating' it takes a power of 840 W. Calculate the current and resistance in each case.
Give a scientific reason:
For electric power transmission, copper or aluminium wire is used.
An electric iron of 1100 W is operated for 2 hrs daily. What will be the electrical consumption expenses for that in the month of April? (The electric company charges Rs 5 per unit of energy).
Statement 1 : Electric current ( flow of electrons ) creates heat in the resistor.
Statement 2 : Heat in the resistor is created according to the rule of energy conservation.
Explain Statement 1 with the help of Statement 2.
Why does tungsten metal used to make solenoid type coil in an electric bulb?
Name any six domestic appliances based on the heating effect of electric current.
In an electric bulb, coil of _______ metal is used.
The electricity bill specifies the usage in _______.
A coil of an alloy _______ is used in electric heater cooker as a resistor.
Which metal is used to make the filament of an electric bulb?
What is used to turn off the sudden increase in current in the electrical circuit of the house nowadays?
How can overloading be avoided?
True or False – If False give the correct answer
The fuse wire does not melts whenever there is overload in the wiring.
Define fuse.
Explain the heating effect of electric current.
Heating effect of current is called ______
Which of the following is correct?
A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of:
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit another set of three bulbs of the same wattage are connected in parallel to the same source.
- Will the bulb in the two circuits glow with the same brightness? Justify your answer.
- Now let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason.
Can we use the same fuse in a geyser and a television set? Explain.
Your teacher has shown you the following activity.
Activity: Teacher has wound a long insulated piece of wire around an iron nail in the form of a coil. Free ends of the wire are connected to a cell through a switch as shown in the following figure. The current is switched on and some pins are placed near the ends of the nail.
Write down any three questions that come to your mind about this activity.
What are the factors affecting heating effect of electric current?
Match the following
| 1. | Bulb | a. | Conductor |
| 2. | Electroplating | b. |
Insulator |
| 3. | Pure water | c. | Heating effect of current |
| 4. | Salt solution | d. | Chemical effect of current |
Name a few appliances which work on the basis of the heating effect of current.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
Tara, after completing her exams, went to her grandmother's house along with her younger brother Rahul. One day, Rahul came home after playing and switched on the fan and air conditioner. At the same time, his grandmother was preparing a milkshake for him using a mixer. Suddenly, they heard a big sound and the electricity of the house got shut down. Tara is called an electrician. He said the main reason for supply to shut down was overloading.
- What is overloading?
- Is overloading and short the same? When does short-circuiting take place?
- How can the effects of overloading be avoided?
Two students decided to investigate the effect of water and air on iron object under identical experimental conditions. They measured the mass of each object before placing it partially immersed in 10 ml of water. After a few days, the object were removed, dried and their masses were measured. The table shows their results.
| Student | Object | Mass of Object before Rusting in g |
Mass of the coated object in g |
| A | Nail | 3.0 | 3.15 |
| B | Thin plate | 6.0 | 6.33 |
What might be the reason for the varied observations of the two students?
The graph of voltage vs current for four different materials is shown below.
Which of these four materials would be used for making filament of bulb?
